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With the advancement of sensor technology and data processing capacities, various types of high volume data are available for process monitoring and prognostics in manufacturing systems. In a broaching process, a multi-toothed broaching tool removes material from the workpiece by sequential engagement and disengagement of multiple cutting edges. The quality of the final part, including the geometric integrity and surface finish, is highly dependent upon the broaching tool condition. Though there has been a considerable amount of research on tool condition monitoring and prognostics for various machining processes, the broaching process is unique in the following aspects: 1) a broaching process involves multiple cutting edges, which jointly contribute to the final part quality; 2) the resharpening and any other process adjustments to the tool can only be performed with the whole broaching tool or at least a whole segment of the tool replaced. The overarching goal of this research is to explore how engineering knowledge can be used to improve process monitoring and prognostics for a complex manufacturing process like broaching. This dissertation addresses the needs for developing new monitoring and prognostics approaches based on various types of data. Specifically, the research effort focuses on 1) the use of in-situ force profile data for real-time process monitoring and fault diagnosis, 2) degradation characterization for broaching processes on an individual component level based on image processing; and 3) system-level degradation modeling and remaining useful life prediction for broaching processes based on multiple images. / Ph. D. / Big data have been providing both opportunities and challenges for product quality assurance and improvement in modern manufacturing systems. In aerospace industry, broaching processes are one of the most important manufacturing processes as they are used to produce the turbine discs in the jet engine. Nonconforming turbine disc quality, either in terms of compromised surface finish or geometry accuracy, will lead to malfunction or even catastrophic failures in the aircraft engines. One of the major sources that lead to nonconforming product quality is excessive tool wear accumulation and other abrupt malfunctions of the broaching tools. In broaching processes, multiple cutting edges are sequentially pushed or pulled through the workpiece, and each cutting edge is responsible to shape the workpiece into a specific intermediate shaped contour. Therefore, a broaching process can be regarded as a multistage manufacturing process with variation propagating through the multiple cutting edges. The overarching goal of this dissertation is to explore how process knowledge can be used to improve process monitoring and prognostics for a complex manufacturing process like broaching. This dissertation focuses on the quality assurance and improvement for broaching processes which includes: 1) timely abrupt process fault detection; 2) tool performance degradation quantification; and 3) remaining tool life prediction, which contributes to both methodological development and practical applications in advanced sensing analytics in manufacturing systems.

Este trabalho propõe um módulo básico de aquisição e pré-processamento de imagem colorida aplicado a robôs móveis, implementado em hardware reconfigurável, dentro do conceito de sistemas SoC (System-on-a-Chip). O módulo básico é apresentado em conjunto com funções mais específicas de pré-processamento de imagem, que são utilizadas como base para a verificação das funcionalidades implementadas no trabalho proposto. As principais funções realizadas pelo módulo básico são: montagem de frames a partir dos pixels obtidos da câmera digital CMOS, controle dos diversos parâmetros de configuração da câmera e conversão de padrões de cores. Já as funções mais específicas abordam as etapas de segmentação, centralização, redução e interpretação das imagens adquiridas. O tipo de dispositivo reconfigurável utilizado neste trabalho é o FPGA (Field-Programmable Gate Array), que permite maior adequação das funções específicas às necessidades das aplicações, tendo sempre como base o módulo proposto. O sistema foi aplicado para reconhecer gestos e obteve a taxa 99,57% de acerto operando a 31,88 frames por segundo. / This work proposes a basic module for a mobile robot color image capture and pre-processing, implemented in reconfigurable hardware based on SoC (System-on-a-Chip). The basic module is presented with a specifics image pre-processing function that are used as a base for verify the functionalities implemented in this research. The mains functions implemented on this basic module are: to read the pixels provide by the CMOS camera for compose the frame, to adjust the parameters of the camera control and to convert color space. The specifics image pre-processing functions are used to do image segmentation, centralization, reduction and image classification. The reconfigurable dispositive used in this research is the FPGA (Field-Programmable Gate Array) that permit to adapt the specific function according to the application needs. The system was applied to recognize gesture and had 99,57% rate of true recognition at 31,88 frames per second.

<p>This study is a thesis for the Master of Science degree in Media Technology and Engineering at the Department of Science and Technology, Linkoping University. It was accomplished from November 2002 to May 2003. </p><p>Objective image quality measures play an important role in various image processing applications. In this paper quality measures applied on halftoned images are aimed to be in focus. Digital halftoning is the process of generating a pattern of binary pixels that create the illusion of a continuous- tone image. Algorithms built on this technique produce results of very different quality and characteristics. To evaluate and improve their performance, it is important to have robust and reliable image quality measures. This literature survey is to give a general description in digital halftoning and halftone image quality methods.</p>

An Inverted double pendulum is a combination of two individual pendulums which represents an example of a nonlinear and unstable dynamic system and it is also a good example of a physical system which can exhibit chaotic behavior.This document contains a first analysis of the model and the control of this system. Also presented is the installation of the electrical materials needed to control the system contain instrumenting the motor, current measurement system, motor shaft angle sensor, vision systemand MYRIO which is an embedded hardware device created by National Instruments will be used for data acquisition and control the system

Made available in DSpace on 2014-12-17T14:56:22Z (GMT). No. of bitstreams: 1 KelsonRTA.pdf: 822338 bytes, checksum: 2e3a06ae915ace956aac24995e24973f (MD5) Previous issue date: 2001-03-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Navigation based on visual feedback for robots, working in a closed environment, can be obtained settling a camera in each robot (local vision system). However, this solution requests a camera and capacity of local processing for each robot. When possible, a global vision system is a cheapest solution for this problem. In this case, one or a little amount of cameras, covering all the workspace, can be shared by the entire team of robots, saving the cost of a great amount of cameras and the associated processing hardware needed in a local vision system. This work presents the implementation and experimental results of a global vision system for mobile mini-robots, using robot soccer as test platform. The proposed vision system consists of a camera, a frame grabber and a computer (PC) for image processing. The PC is responsible for the team motion control, based on the visual feedback, sending commands to the robots through a radio link. In order for the system to be able to unequivocally recognize each robot, each one has a label on its top, consisting of two colored circles. Image processing algorithms were developed for the eficient computation, in real time, of all objects position (robot and ball) and orientation (robot). A great problem found was to label the color, in real time, of each colored point of the image, in time-varying illumination conditions. To overcome this problem, an automatic camera calibration, based on clustering K-means algorithm, was implemented. This method guarantees that similar pixels will be clustered around a unique color class. The obtained experimental results shown that the position and orientation of each robot can be obtained with a precision of few millimeters. The updating of the position and orientation was attained in real time, analyzing 30 frames per second / A navega??o baseada em realimenta??o visual para rob?s, trabalhando em um ambiente fechado, pode ser obtida instalando-se uma c?mera em cada rob? (sistema de vis?o local). Esta solu??o, entretanto, requer uma c?mera e capacidade de processamento embarcado para cada rob?. Quando poss?vel, um sistema de vis?o global ? uma solu??o barata para este problema. Neste caso, uma ou uma pequena quantidade de c?meras, cobrindo todo o espa?o de trabalho, pode ser compartilhada pelos rob?s, diminuindo o custo de uma grande quantidade de c?meras e o hardware de processamento necess?rio a um sistema de vis?o local. Este trabalho apresenta a implementa??o e os resultados experimentais de um sistema de vis?o global para uma frota de mini-rob?s m?veis, utilizando como plataforma de testes uma partida de futebol entre rob?s. O sistema de vis?o proposto consiste de uma c?mera, uma placa digitalizadora de imagens e um computador (PC) para o processamento das imagens. O PC ? respons?vel pelo controle dos rob?s, baseado em realimenta??o visual, enviando comandos aos rob?s atrav?s de um transmissor de r?dio. Com o objetivo de possibilitar ao sistema reconhecer unicamente cada rob?, eles possuem r?tulos em seu topo, consistindo de dois c?rculos coloridos. Algoritmos de processamento de imagem foram desenvolvidos para o c?mputo eficiente, em tempo real, da posi??o (rob? e bola) e orienta??o (rob?) dos objetos em campo. Um grande problema encontrado foi rotular a cor, em tempo real, cada ponto colorido da imagem, em condi??es de varia??o de luminosidade. Para resolver este problema, um software de calibra??o autom?tica da c?mera, baseado no algoritmo de aglomera??o K-means, foi implementado. Este m?todo garante que pixels similares sejam agrupados ao redor de uma ?nica classe de cor. Os resultados experimentais obtidos mostram que a posi??o e a orienta??o de cada rob? pode ser obtida com uma precis?o de poucos mil?metros. A atualiza??o das informa??es de posi??o e orienta??o foi realizada em tempo real, analisando 30 quadros por segundo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Vision, the human being s favorite sense, and its great capacity to obtain, to process and to interpret great amount of visual nature data has been throughout the years a great inspiration for development of techniques and technological devices that reproduce it into a computational system. In welding processes, vision can supply information in inspection and welded joint s quality, in the parameters monitoring, in trajectory correction and even, finally, in the study of the phenomena involved in the process. However, the luminosity/radiation emitted from the weld arc represents a barrier for these studies based in the process visualization. One of the forms currently used to visualize the process, without the interference of the arc s light, consists of illuminating the process with the near infrared light and, using band pass (interference) filters, around this exactly wave length, during the acquisition of the images. A solution for the near infrared illumination, of increasing application, involves the use of laser diodes of high power, with low cost and less complex installation than conventional lasers. Therefore, the proposal of this work is the project, construction and assessment of a vision system for welding processes with low cost and high flexibility. It is based on characterization of the spectrum of the weld arc, definition of a drive topology for the laser diode within its limitations of use and maximizing the emitted luminous power, built of control circuits, selection of optics equipment and components and, finally, project and application of a prototype for visualization of different arc-welding processes. The electrical system was validated by computational simulations and experimental burnout and stress tests. The final assessment of the whole vision system was carried out during TIG and MIG/MAG welding. Although, during the welding, the system was not capable of overcome the arc radiation, it provides a homogenous illumination in synchronism with the camera, which represents the main limitation due to its large shutter. Eventually, it s suggested to employ the developed vision system for helping joint tracking. / A visão, o sentido predileto do ser humano, e sua grande capacidade de captar, processar e interpretar grandes quantidades de dados de natureza visual tem sido, ao longo dos anos, um grande estímulo para o desenvolvimento de técnicas e de dispositivos tecnológicos que a reproduzam um sistema computacional. Nos processos de soldagem, a visão pode fornecer dados desde na inspeção e qualidade da junta soldada, no monitoramento de parâmetros, na correção de trajetórias até, por fim, no estudo dos fenômenos envolvidos no processo. Porém, a radiação luminosa emitida pelo arco representa uma barreira para tais estudos baseados na visualização do processo. Uma das formas utilizadas atualmente para se obter a visualização do processo, sem a interferência do arco, consiste em iluminar o processo com o infravermelho próximo e utilizar filtros de interferência (passa-faixa), em torno deste mesmo comprimento de onda, durante a aquisição das imagens. Uma solução para a iluminação infravermelha, de aplicação crescente, envolve o uso de diodos laser de alta potência, com baixo custo e menor complexidade de instalação do que os lasers convencionais. Desta forma, a proposta deste trabalho foi a criação de um sistema de visão dos processos de soldagem a arco, de baixo custo e alta flexibilidade, indo desde a caracterização dos espectros de emissão luminosa do arco, passando pela criação de uma topologia de acionamento para o diodo de alta potência no infravermelho próximo, respeitando suas limitações de uso e maximizando a potência luminosa emitida, criação dos circuitos de controle, escolha dos equipamentos e componentes ópticos e, por fim, projeto e aplicação de um protótipo em processos de soldagens. O sistema elétrico foi validado por simulações computacionais e testes experimentais de burnout e de stress, e as limitações do sistema de visão, como um todo, foram encontradas através e sua aplicação com soldagens TIG e MIG/MAG. Nestes ensaios, embora não tenha sido capaz de sobrepor a luz do arco, o sistema desenvolvido proporcionou uma iluminação homogênea e em sincronia com a câmera, onde a principal limitação foi o grande tempo de exposição da câmera disponível. Sugere-se, ao final, utilizar o sistema na forma de um seguidor de juntas. / Mestre em Engenharia Mecânica

This study is a thesis for the Master of Science degree in Media Technology and Engineering at the Department of Science and Technology, Linkoping University. It was accomplished from November 2002 to May 2003. Objective image quality measures play an important role in various image processing applications. In this paper quality measures applied on halftoned images are aimed to be in focus. Digital halftoning is the process of generating a pattern of binary pixels that create the illusion of a continuous- tone image. Algorithms built on this technique produce results of very different quality and characteristics. To evaluate and improve their performance, it is important to have robust and reliable image quality measures. This literature survey is to give a general description in digital halftoning and halftone image quality methods.

L'objectif principal de ce travail de thèse est l'élaboration d'un système de vision binoculaire mettant en oeuvre deux caméras de types différents. Le système étudié est constitué d'une caméra de type omnidirectionnelle associée à une caméra PTZ. Nous appellerons ce couple de caméras un système de vision hybride. L'utilisation de ce type de capteur fournit une vision globale de la scène à l'aide de la caméra omnidirectionnelle tandis que l'usage de la caméra mécanisée permet une fovéation, c'est-à-dire l'acquisition de détails, sur une région d'intérêt détectée depuis l'image panoramique.Les travaux présentés dans ce manuscrit ont pour objet, à la fois de permettre le suivi d'une cible à l'aide de notre banc de caméras mais également de permettre une reconstruction 3D par stéréoscopie hybride de l'environnement nous permettant d'étudier le déplacement du robot équipé du capteur. / The primary goal of this thesis is to elaborate a binocular vision system using two different types of camera. The system studied here is composed of one omnidirectional camera coupled with a PTZ camera. This heterogeneous association of cameras having different characteristics is called a hybrid stereo-vision system. The couple composed of these two cameras combines the advantages given by both of them, that is to say a large field of view and an accurate vision of a particular Region of interest with an adjustable level of details using the zoom. In this thesis, we are presenting multiple contributions in visual tracking using omnidirectional sensors, PTZ camera self calibration, hybrid vision system calibration and structure from motion using a hybrid stereo-vision system.